Neville's Island (ITV), Tim Firth's adaptation of his own stage comedy, usefully supplied its own synopsis. "They make films about this don't they," says Neville brightly, after he and his three colleagues find themselves stranded during a corporate team-building exercise. "People on islands ... shipwrecked... and what happens is they gradually go back to nature and shed 20th-century values, and the power relationships change, and they tell each other dark secrets that release hidden qualities, and, in the end, there's a showdown between the one they thought was weakest and the one they thought was the leader."

This speech is a slightly hazardous one for the drama, because although it leaves open the question of who will eventually triumph, it also risks making everything that follows it feel as inevitable as the compulsory figures in an ice-skating competition. Will the writer fall flat on his face when it comes to the tricky Atavistic Instincts scene? How will he carry off that demanding twist when apparent superiority reveals itself as vulnerability? The answer is, pretty well, if not quite, a row of perfect sixes.

The cast, on the other hand, was flawless - Timothy Spall, David Bamber, Martin Clunes and Jeff Rawle offering a comprehensive palette of male inadequacy - from Spall's boorish Gordon, who supplies a sardonic footnote for every feeble comment from his colleagues, to Bamber's comically over- equipped Angus, whose enormous rucksack contains enough equipment for an Everest expedition; "Didn't Julie pack you a small armoured car?" says Gordon, witheringly, as the four men arm themselves to confront the beast they believe is stalking their little patch of wilderness.

The party is completed by Roy, a born-again Christian with a history of mental problems and Neville, a doggedly benign figure who is the nominated leader of the group. Before very long Roy is up a tree smeared in blood and singing "Morning Has Broken", and Gordon has vandalised his corporate future, having used Angus's mobile phone as an impromptu trout-club and made insinuations about the fidelity of his wife - unwise given that Angus is soon to become his boss.

With a slightly startling speed the denouement disassociated itself from Gordon - whose gift for sarcasm had been a lifesaver on the island - and sided with Neville, now revealed as a representative of basic human decency, rather than ineffectual figure of fun. There was a sense here that some subtleties had been crumpled out of shape in the compression from stage play to television film, in particular a rich theme about how jokes can serve as antlers for rutting corporate males. But enough of Firth's thoughtful, sharply crafted comedy had survived to make the experience very enjoyable.

I didn't have enough room yesterday to detail the full fatuity of Nicholas Owen's film about the death of Diana - my favourite moment being the Top Gear sequence, in which the reporter drove a similar type of Mercedes through the underpass and murmured darkly about its latent power - "I'm having difficulty holding it back to be honest," he said, as if it might have been in on the conspiracy. That was closely followed by the lachrymose pan round the interior of Dodi's flat - including a poignant close-up of two matching bathrobes, forever to remain undampened.

But if Diana: the Secrets behind the Crash (ITV) counted as an open sore in the schedules, at least it wasn't long before someone supplied a plaster. Dispatches' film about that night was everything that Owen's wasn't - sober, sceptical and persuasive. It offered confirmation for what should have been obvious from the night before - that Mohamed Al Fayed is prepared to say virtually anything that will distract attention from the failures of his associates.

Instead of Owen's tantalising mousse of sentiment and dark insinuation you were offered a solid pudding of a programme, in which the accounts of Fayed's employees were contradicted by new witnesses. In a statement to the French police, the Ritz barman on duty that night also said that he had been asked by senior Ritz management to adjust his account of what he saw "for the good of the Royal Family".

The conclusion was simple - Henri Paul was drunk and Diana's death was an avoidable accident. As headlines go this doesn't quite have the zippy allure of "Were they murdered?", just the old-fashioned virtue of some acquaintance with reality.